1. Field of the Invention
The present invention relates to a fixture for retaining an end of a member, such as a section of a windmill tower, a blade for a windmill, or a hub for a wind mill turbine, the fixture comprising an axial control/retaining means in relation to the longitudinal axis of the member in form of a first lower console for preventing of a relative horizontal displacement between the end of the member and the fixture in a direction perpendicular to the end of the member in use, the console further including cross-positioning means for positioning the end of the member in relation to the fixture during fastening of the fixture to the end of the member in relation to a horizontal oriented direction parallel to the end of the member in use, and cross-axial holding means for preventing of a relative displacement between the end of the member and the fixture in a direction across of the longitudinal axis of the member, first connection devices for attachment of the fixture to an external structure different from the end of the member, and parts cooperating with at least two second connection devices for releaseable attachment of mainly vertically oriented frame parts upstanding from the fixture.
2. Description of Related Art
Members, in particular wind turbine tower sections, are typically cylindrical and slightly conical, and the ends have an internal flange with a plurality of holes, mainly for use in connecting of the sections of the wind mill on site. However, the ends might also have flanges on the outside for assembling of the sections, but outside flanges are primarily used in connection of wind mill towers to a foundation. The tower sections typically have an outside diameter between 2 to 5 meters, a weight of 10 to 80 tons, and a length of approximately 10 meters, and in certain circumstances, even larger dimensions than the above indicated are used. Retaining and handling such sections during transport is thus far from a routine task. In most cases, the relocation of a wind mill tower from the production site to the operation site includes more than one category of transportation. The transport will typically consist of two or more transports on sea, railway and road, and thus, reloading of the tower sections is not an insignificant task to perform due to the size and weight of the sections.
Such a fixture is, among others, known from International Patent Application Publication WO 2007/093854 (Vestas A/S) where the control/retaining means comprises displaceable and pivotally mounted locking elements, with through openings for admission of bolts which are passed through flanges in an adjacent end of the member to be secured. The locking elements are naturally manufactured of high performance steel, and the locking elements are thus relative heavy and difficult to handle for the workers who are intended to secure the end of the member to the control/retaining means. The displaceable and pivotable mounting of the locking elements in the control/retaining means results in that the holes in them can be positioned with a hole in a flange in the end of a member which is to be secured, however within the flange dimensions and hole patterns in flanges to which the control/retaining means is designed. The known fixture has thus a certain, but still limited flexibility in use, understood in that way, that the limits for displacement and pivoting of the locking elements sets the limits for which diameters and hole patterns the fixture the fixture is useable for. Further, the work with the correct positioning of the holes in the locking elements might be considerably time consuming.
The fixture also has a frame part that is upstanding from the control/retaining means and comprising three parallel columns interrelated by three transversal beams, where the middle column comprises a through going track in which is put through and secured a locking device comprising a threaded rod with adjustable nuts for securing/clamping on each side of the middle column, and which, opposite the flange in the end of the member facing side, comprises a plate shaped body with elongated fit holes, for receiving of bolts for clamping in the flange in the end of the member. Due to the fact that the sections in wind turbine towers most frequently have a conical shape, there will naturally occur a certain space between the plate shaped body which is clamped in the flange in the end of the member and the mounting of threaded rod in the middle column. Under heavy cross oriented force impacts on the member, this leads to a very hard load on the threaded rod, which demands for large strength requirements to as well the middle column, as to the threaded rod and its anchoring in the column, which results in that it will be relatively costly.